分散液液微萃取

Dispersive by microvolume Saadat Rastegarzadeh Department of Chemistry,detection.

Analysis of fungicide thiram in environmental and agricultural samples was performed.

a r t i c l e i n f o Article history:

Received 11February 2013

Received in revised form 7May 2013Accepted 8May 2013

Available online 23May 2013

Keywords:Thiram

Dispersive liquid–liquid microextraction Microvolume spectrophotometry

a b s t r a c t

A novel and simple method for the sensitive determination of trace amounts of fungicide thiram is devel-oped by combination of dispersive liquid–liquid microextraction (DLLME)and microvolume UV–vis spectrophotometry.The method is based on the conversion of thiram to a yellow product in the presence of ethanolic potassium hydroxide and copper sulfate,and its extraction into CCL 4using DLLME technique.In this method the ethanol existing in ethanolic KOH plays as disperser solvent and a cloudy solution is formed by injection of only CCl 4as extractant solvent into sample solution.Under the optimum condi-tions,the calibration graph was linear over the range of 25–1000ng mL À1of thiram with limit of detec-tion of 11.5ng mL À1.The relative standard deviation (RSD)for 100and 500ng mL À1of thiram was 2.7and 1.1%(n =8),respectively.The proposed method was successfully applied to determination of thiram in water and plant seed samples.

Ó2013Elsevier B.V.All rights reserved.

Introduction

Dithiocarbamates (DTCs)are a group of organosulfur com-pounds that have been extensively used as pesticides in agriculture and horticulture over several decades [1,2].DTCs can be catego-rized into three subclasses depending upon their carbon skeleton including dimethyldithiocarbamates (DMDs),ethylenebis (dithio-carbamates)(EBDs),and propylenebis (dithiocarbamates)(PBDs).Among these,thiram (tetramethyl thiuram disulfide)(Fig.1)is a well-known dithiocarbamate fungicide that has been in commer-cial use since 1925[3].Thiram is widely used to prevent crop dam-age in the field and to protect harvested crops from deterioration in storage or transport and is also used as a seed protectant to control a

number of fungal diseases [4].Therefore,it extensively applied as a foliar treatment on fruits,vegetables,ornamentals and turf crops from a variety of fungal diseases.In addition,it is used as an animal repellent to protect fruit

trees and ornamentals from damage by rabbits,rodents,and deer.Thiram is also used in rubber industry,in the treatment of human scabies,as a sunscreen,and as a bacte-ricide in soap [5–7].Although the usability of this dithiocarbamate compound is unassailable,its increasing application results in

1386-1425/$-see front matter Ó2013Elsevier B.V.All rights reserved./10.1016/j.saa.2013.05.020

Corresponding author.Tel./fax:+986113331042.

E-mail addresses:rastegarz@ ,rastegarz@scu.ac.ir (S.Rastegarzadeh).